In a communication network the traffic is intended to be distributed according to specific rules in a regular manner to all nodes and lines in the communication network, also referred to as the network.
With this type of distribution what is known as a ‘distribution fan’ results for every communication relation from a specific input A to a specific output B, said distribution fan comprising all the nodes and connecting routes that can expediently be used for this communication relation (see FIG. 1 and the relevant passages in DE 10161547.7). In a correspondingly meshed network the distribution fans of different communication relations of necessity overlap so that either identical or partially overlapping or even totally disjoint ‘branch patterns’ result at the individual nodes (see FIG. 2). The overlap is thereby a function of the distribution mechanisms operating in the network nodes.
The following mechanisms are known to date for the individual distribution of data packets to outgoing groups:    1) Simple distribution of the incoming traffic to an outgoing group without priorities:    (a) Prior distribution of the traffic into individual queues per port:            A central traffic distributor distributes the incoming traffic to individual queues, each of which is assigned to precisely one outgoing port of the group. Distribution can be cyclical or (e.g. in the case of different port bandwidths) weighted according to different criteria. The current capacity of the individual queues (based on the number of packets or in the case of variable packet lengths based on the actual quantity of data in bytes) or the individual length of the data packet to be assigned in that instance can for example be taken into account. The ports generally manage the queues according to the FIFO principle. Anything in a queue must then also be processed by the assigned port.            (b) Use of a single queue with a multiserver principle:            A favorable distribution of the traffic with optimum utilization of the available port capacities can be achieved with the multiserver principle. Here all incoming data is placed in a single queue, from which the ports, whenever they are free or become free, collect the next packet to be processed according to a FIFO (First In First Out) principle.            2) Distribution of the incoming traffic to an outgoing group with priorities:    (a) Prior distribution of the traffic into individual priority queues per port:            A central traffic distributor distributes the incoming traffic to individual queues, whereby an individual queue is provided for each priority class for every outgoing port. The variants according to 1(a) can be used in the same way. When processing the queues, the ports take the priorities into account according to the corresponding rules (‘strict’, ‘weighted’, etc.).            (b) Multiserver principle with one queue per priority class:            As 1(b), whereby the higher priority queues are processed in a preferred manner according to the priority rules.            3) Distribution of the incoming traffic to an outgoing group with priority-controlled Per Flow Queuing:            A refinement of the elementary mechanisms disclosed above involves also setting up individual and separate queues per flow for granular differentiation and prioritization of different individual communication relations (flows). However this multiplies the complexity of queuing (due to the number of queues) and scheduling (due to selection of the next packet to be output from the plurality of queues) and makes it very much more a function of the traffic patterns (i.e. number of simultaneously active flows). It must also be ensured that there is fair distribution of resources between flows with equal priority, for which specific mechanisms such as Weighted Fair Queuing (WFQ) etc. can be used, the complexity of which (particularly when there is a very large number of queues) can significantly exceed that of a simple priority queuing system. Naturally Per Flow Queuing can be used in a port-specific manner [above pattern (a)] as well as in conjunction with the multiserver principle [above pattern (b)].            4) ECMP (Equal Cost Multiple Path):            ECMP provides for distribution to a plurality of ports. Only those ports of a transmission node are taken into account here, the linked physical lines of which lead to the same adjacent transmission node. In this way (i.e. by load distribution to a plurality of physical lines) the transmission capacity between two adjacent transmission nodes can be increased, even if the transmission capacity of an existing single physical line cannot be increased further.        
With all the known methods, during implementation in the queues only one indicator (address) is generally stored to identify the respective data packet in a generally shared data storage unit. The processing sequence results implicitly from the sequence of entries in the queue (e.g. according to the FIFO principle) or from the previous method for selecting the next queue to be processed (e.g. based on priority and where the priorities are the same e.g. cyclically, longest queue first, shortest queue first, as a function of weighting as with WFQ).
In order to achieve additional specific effects, further information can be included in this scheduling decision. There is very frequently a need for Traffic Shaping in ATM technology in particular (but also in isolated cases in the IP environment). This method is intended to ensure that in general specific bandwidths are complied with, usually achieved by corresponding distance criteria between the cells (packets) of a connection (i.e. communication relation). Additional time information is stored for this purpose specifying an earliest, latest and/or optimum processing time for a queue or a specific cell (packet) (known as the calendar).
The mechanisms can also be extended with the same effect for application to a plurality of groups, in so far as these groups either do not overlap at all (are disjoint) or overlap completely (are identical). A solution for a fair and efficient packet-based traffic distribution to partially overlapping groups taking into account priorities is however not known.